AU702003B2 - Saccharomyces-specific antigens and antibodies, their preparation and use - Google Patents

Description

MIUMI 1 2815/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 0 .4 4 *4 ~0 0 0 9 *04000 9 9 09 0 0 0 00 0 0*~'04* 0 *0 *J 0 0 0 4~ 0 00 Application Number: Lodged: Invention Title: SACOHAROMYCES-SPECIFIC ANTIGENS AND ANTIBODIES, THEIR PREPARATION AND USE The following statement is a full description of this inveuation, including the best method of performing it known to us

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BEHRINGWERKE AKTIENGESELLSCHAFT HOE 94/B 001 Ma 986 Dr.Bc/hg Saccharomyces-specific antigens and antibodies, their preparation and use The invention relates to antigens which are specific for Saccharomyces cerevisiae, Saccharomyces bayanus, Saccharomyces paradoxus and Saccharomyces pastorianus, and to antibodies directed against them. These antigens and antibodies can be employed for identifying and quantifying the said Saccharcmyces species.

According to van der Walt P. van der Walt [1970], Genus 16, pp. 555-718), 41 species are assigned to the genus Saccharomyces. In the interim, however, a whole string of these species have been assigned to other S 15 genera and renaming has taken place within the Saccharomyces genus. Currently, 10 species are accepted within the Saccharomyces genus (Barnett, J. A. [1992] Yeast, 8, pp. 1-23).

t* These 10 Saccharomyces species are: S. bay Qus, S. castellii, S. cerevisiae, S. dairensis, S. exiguus, S. kluyveri, S. paradoxus, S. pastorianus, S. servazzii, S. unisporus..

In the future, this classification, too, will in turn undergo changes since the rules and criteria by which taxonomic categorization of yeast species is undertaken are being changed. For example, it could be argued that the species S. bayanus, S. paradoxus and S. pastorianus are in no way to be regarded as independent species but Srather as varieties of S. cerevisiae.

Finally, it remains to observe that the systematics of the yeast genus Saccharomyces are of practical importance since some species are used in industry, in particular in the beer and wine industry, in the baking industry and in I U j7777 2biotechnology, and, for this reason, over and above the academic interest, there must be clear classifications which are universally accepted.

In imitation of Naumov et al. (1992) Yeast, 8, pp. 599- 612, the following terminology is used for describing the present invention: Saccharomyces cerevisiae, Saccharomyces bayanus, Saccharomyces paradoxus and Saccharomyces pastorianus are combined as "Saccharomyces sensu stricto", in contrast to "Saccharomyces sensu lato", which is used to designate Saccharomyces castellii, Saccharomyces dairensis, Saccharomyces exiguus, Saccharomyces kluyveri, Saccharomyces unisporus and Saccharomyces servazzii.

The yeast species are classified taxonomically first and 15 foremost by morphological and physiological criteria (such as, for example, the utilization of carbon sources, dependence on growth factors, utilization of nitrogen sources, and the like) and also by mating behavior. DNA analysis is also being increasingly used for determining 20 relationships between yeast genera and yeast species. On the other hand, immunological methods are only rarely employed for differentiating yeast species. One reason for this is that antibodies which are directed against cell wall-specific antigens crossreact to a large extent, both within a genus and beyond genera. The reason for the crossreactivity within the genus Saccharomyces is that the cell wall-associated glycoproteins carry carbohydrate side groups which are made up of mannose chains which do not differ, or hardly differ, from species to species.

There is also such a high degree of structural homology at the level of the polysaccharides (mannans and glucans) that any differentiation using antibodies would seem to be very difficult to achieve.

The difficulty in obtaining antibodies which are specific for a particular yeast species, in particular r S. cerevisiae, is evident, for example, from Kumar et al.

y 1 3 (Infection and Immunity, 1840 (1985), pp. 806-812). The authors report that antibodies which were in each case prepared, in rabbits, against a representative of the species Histoplasma capsulatum, Candida albicans or Saccharomyces cerevisiae in each case also crossreact with the antigens of the other two species.

Consequently, the underlying object of the present invention was to prepare antibodies which react specifically with one or a few yeast species and thus render it possible to differentiate these yeast species from others.

The object was achieved by the preparation of monoclonal antibodies which, surprisingly, recognize the yeast species Saccharomyces cerevisiae, Saccharomyces bayanus, 15 Saccharomyces paradoxus and Saccharomyces pastorianus (Saccharomyces sensu stricto, see above) specifically.

These antibodies are directed against a cell wall-associated antigen and may be employed in various immunological detection systems, such as Western blot, immuno- 20 fluorescence test, enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA) and fluorescence immunoassay (FIA). The hybridoma culture which secretes the novel antibody, a murine monoclonal antibody (Mab 92-276/018), was deposited with the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSM) (German Collection of Microorganisms and Cell Cultures), Mascheroder Weg 1 B, 38124 Braunschweig, on 22.04.1993 under the number DSM ACC2126.

The present invention therefore relates to the monoclonal antibody Ma1f2-276/018 from the hybridoma having the deposition number DSM ACC21,-6.

The invention also relates to epitopes or immunogenic moieties from Saccharomyces sensu stricto, preferably I from Saccharomyces cerevisiae, to which the monoclonal antibody/DSM ACC2126 binds.

i 4 -4- The invention furthermore relates to monoclonal or polyclonal antibodies which bind to epitopes or immunogenic moieties of Saccharomyces sensu stricto, preferably Saccharomyces cerevisiae, and which possess the same antigenic specificity as the monoclonal antibody DSM ACC2126. Such antibodies can be isolated, for example, by means of competition experiments using the Mab DSM ACC2126.

The present invention furthermore relates to a diagnostic agent for identifying, or for quantitatively detecting, Saccharomyces sensu stricto, which diagnostic agent contains the monoclonal antibody DSM ACC2126 or a monoclonal or polyclonal antibody which binds to epitopes or immunogenic moieties of Saccharomyces sensu stricto, 15 preferably Saccharomyces cerevisiae, and which possesses the same antigenic specificity as the monoclonal antibody S. DSM ACC2126.

The present invention additionally relates to a diagnostic agent for detecting antibodies against Saccharomyces ."20 sensu stricto, which diagnostic agent contains epitopes or immunogenic moieties from Saccharomyces sensu stricto, preferably Saccharomyces cerevisiae, to which the monoclonal antibody DSM ACC2126 binds.

The invention furthermore relates to a process for preparing monoclonal antibodies, wherein immunogenic S moieties from Saccharomyces sensu stricto, preferably Saccharomyces cerevisiae, which react with the monoclonal antibody DSM ACC2126 are isolated, wherein a suitable organism is immunized with these isolated antigens or immunogenic moieties, and wherein, of the resulting monoclonal antibodies, those are selected which are specific for Saccharomyces sensu stricto.

SThe present invention also relates to a method for Sidentifying or quantifying Saccharomyces sensu stricto in a sample, wherein the sample is brought into contact with one of the above-described Saccharomyces sensu strictospecific antibodies and the formation of antigen/antibody complexes is then measured using suitable methods.

The invention finally relates to a method for detecting antibodies against Saccharomyces sensu stricto in a sample, wherein the sample is brought into contact with the above-described epitopes or immunogenic moieties from Saccharomyces sensu stricto and the formation of antigen/antibody complexes is then measured using suitable methods.

In that which follows, the invention, in particular in its preferred embodiments, is described in detail.

The examples cited below clarify the preparation and usefulness of the monoclonal antibodies described, in 15 particular of the monoclonal antibody 92-276/018 (DSM I ACC2126). With the aid of this antibody, Saccharomyces sensu stricto can be rapidly determined using simple technical methods. It is frequently necessary to identify yeasts in the foodstuffs, beer and wine industries and 9.

20 also for quality control in the pharmaceutical industry, for example when culturing S. r-revisiae (syn. S.

boulardii) as a drug which is employed for treating diarrheas or when preparing recombinant proteins in S. cerevisiae.

25 Further possible applications for the monoclonal antibody 92-276/018 are to be found in the clinical sector.

Excessive colonization of the intestine with yeasts can give rise in patients, due to the formation of large amounts of alcohol (gastrointestinal alcohol fermentation), to a so-called "alcohol autointoxication syndrome" ("autobrewery syndrome") which can lead to painful disturbances in the health of the patients and is also of forensic interest.

Following infection with S. cerevisiae, immunosuppressed _I _I 6 patients can contract a fungemia which can even have fatal consequences in extreme cases. Rapid and unambiguous identification of these yeasts with the aid of the monoclonal antibody permits speedy therapy using antibiotics which are suitable for use against S.

cerevisiae.

In addition, the monoclonal antibody can be used to identify yeasts more rapidly in investigations of the type undertaken by Preller et al. Air Waste Managm.

Ass. 39, 1094-1097 [1989]). Chronic, non-specific pulmonary disorders frequently appeared in the inhabitants of a town in the vicinity of which there were a yeast production plant and a penicillin production plant. In order to evaluate whether the yeasts, in this case S.

15 cerevisiae, could be linked causatively with this disease symptom, the number of S. cerevisiae particles per cubic metre of air were determined, as an initial assessment, in the region between the yeast production plant and the town. Using the monoclonal antibody, speedy identification of S. cerevisiae, and, in particular, exclusion of other yeast species, such as, for example, Rhodotorula, which can frequently be found in the air, can be carried out rapidly and reliably.

Preparation of monoclonal antibodies against the glycoprotein gp200 from Saccharomyces cerevisiae: p In order to prepare these antibodies, Balb/c mice which were six to eight weeks old were immunized with a glycoprotein (gp200) which was described by Heelan et al.

(1991) Immunol. Lett. 28, pp. 181-186. The gp200 can be isolated rapidly and simply as follows: S. cerevisiae Sainsbury, PLC) is cultured overnight in YPD medium.

The cells are harvested, washed twice in water and resuspended in 10 times the volume of water. The cell Ssuspension is incubated for 1 hour in a water bath at 100 0 C. The cell preparation is then centifuged for minutes at 5000 rpm in a bench centrifuge (Varifuge 3.2 ii 7 RS) and the supernatant concentrated approximately 3 times using a Centricon 100k filtration system (Filtron).

For the immunization, each mouse was injected subcutaneously with approximately 50 jg of the glycoprotein emulsified in complete Freund's adjuvant and, in a second instance, intraperitoneally. A second and a third immunization without adjuvant were in each case carried out four to eight weeks later. Immediately before the actual fusion, the experimental animals were additionally boosted intravenously on four days in succession. On the day of the fusion, the spleens were removed under sterile conditions and suspended to form individual cells. By means of fusing 108 spleen cells with 2x 10 7 cells of the myeloma cell line SP 2/0 or cell line X 63 Ag 8653 Immunol. 173, pp. 1548-1550, [1979]), hybrid cells r'e. were produced which were subsequently sown in a selection medium (Dulbecco's minimal essential medium, DMEM, supplemented with 20% fetal calf serum FCS, 0.1 mM hypoxanthine, 0.4 mM aminopterin and 16 mM thymidine) on :a 20 culture plates having 24 wells (from Costar) at a concentration of 106 cells/well. Two to three weeks later, o individual cell colonies were isolated from the wells and in each case transferred into a well of a new culture plate.

After a further two to three days, the culture supernatants were screened for the presence of gp200-specific antibodies using an enzyme immunoassay. The supernatants C. were incubated on gp200-coated microtitration plates and any specific antibodies which were present were detected by an anti-mouse peroxidase/immunoglobulin conjugate reaction. Positive cell lines were cultured up and, after testing for the absence of mycoplasmas, were frozen in liquid nitrogen. In parallel with this, positive cell lines were cloned using a micromanipulator. Suitable clones were then multiplied in cell culture (mass culture t in roller bottles). Purification was carried out using ammonium sulfate precipitation and protein A chromatography. Purity was tested by means of HPLC and gel 8 electrophoresis and the immunoglobulin classes determined by Ouchterlony immunodiffusion.

Example 1 Hybridoma supernatants are tested for their reactivity in 5 Western blots using antigen from Saccharomyces cerevisiae and from Schizosaccharomyces pombe as a comparison.

For this purpose, S. cerevisiae (VLSF 07158) and S. pombe (CBS 1043) were cultured for 3 days, at 30°C and at 180 rpm, in YPD medium yeast extract, 2% peptone, 2% glucose) in 250 ml conical flasks on a shaking apparatus.

After centrifuging 10 ml of culture broth in each case, the cells were harvested, taken up in 1 ml of 10 mM Tris buffer (pH provided with glass beads, and disrupted .0 in a glass bead mill. Subsequently, the homogenate was 15 heated in accordance with Laemmli (Nature 227, 680-685 [1970]), fractionated in a 10% SDS polyacrylamide gel and transferred to nitrocellulose membranes (Burnette, Anal.

Biochem. 112, 195-203 [1981]). The nithocellulose strips were then incubated in Tris buffers (10 mM Tris HC1, pH 7.5, 150 mM NaCl, 1% gelatin, 4% tween 20) which in each case contained monoclonal antibodies, at a concentration of approximately 10 pg/ml, from nine different hybridoma supernatants. Anti-mouse antibodies which were coupled to alkaline phosphatase were used as the conjugate. Fast S: 25 Blue B salt (from Serva, Heidelberg) and Naphtol AS-MX Phosphat (from Sigma Chemie, Munich) were used as substrates. Rainbow® protein molecular weight markers (Amersham Buchler GmbH, Braunschweig) were additionally loaded onto the SDS polyacrylamide gel for determining 30 the relative molecular mass.

i All nine antibody specificities recognized antigens from S. cerevisiae in the Western blot.

Of nine supernatants tested, four were only very weakly positive: I 9 -92-285/18 -92-285/27 -92-285/29 -92-275/02 Four supernatants exhibited quite good reactivity: -92-285/5 -92-285/10 -92-285/15 -92-285/16 The strongest reactivity was shown by the supernatant -92-276/018.

.By contrast, none of the nine supernatants recognized an S antigen from S. pombe. This was judged to be the criterion for a specific immunoreactivity of the mono- .15 clonal antibodies.

In subsequent work, the reactivity of the monoclonal 1 antibody 92 276/018 was investigated in more detail.

Example 2 The specificity of the monoclonal antibody 92 276/018 20 (DSM ACC2126) was analyzed in Western blots on the one hand and on intact yeast cells in immunofluorescence tests on the other.

Immunofluorescence on intact yeast cells using monoclonal antibodies was carried out as follows. The yeasts were cultured in media as described for the Western blot analyses. 10 pl of a yeast cell suspension were in each case introduced into the wells of immunofluorescence glass plates. After 1 hour of incubation at RT, theI supernatant was sucked off and the cells were fixed byI adding acetone cooled to 4*C. The plates were then rinsed 30 adin actonecooed o 4C. Te pate wee thn rnse f< 10 with water and dried. 10 p1 of the antibody solution (100 pg/ml) were pipetted into each well. After the plates had been incubated at 37°C in a moist chamber for one hour, the supernatant was removed, the plates were washed three times, and FITC-labeled anti-mouse immunoglobulin conjugate was added.

Microscopic analysis was carried out after the plates had been incubated for one hour and then washed.

Mab 92 276/018 was examined with regard to its reactivity with different yeast species. The different yeast species were obtained from the following institutions: Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSM) (German Collection of Microorganisms and Cell Cultures), Braunschweig, Federal Republic of Germany; 15 Centraalbureau voor Schimmelcultures (CBS) (Central Office for Mould Cultures), Baarn-Delft, Netherlands; Versuchs- und Lehranstalt fur SpiritusfabrikatiQn und Fermentationstechnologie in Berlin (VLSF) (Experimental and Educational Institute for Spirit Production and 0 Fermentation Technology in Berlin), Berlin,, Federal Republic of Germany; Institut fUr Mikrobiologie und Weinforschung (IMW) (Institute for Microbiology and Wine S"t" Research) of the Johannes Gutenberg University, Mainz, Federal Republic of Germany; Yeast Genetic Stock Center (YGSC), Berkeley, USA and J. Sainsbury PLC, London, England. In addition to this, some yeast strains were obtained from research institutes, which strains only have strain designations which are cited in the literature but do not conform to the nomenclature system of any official institute. The following yeast species were employed: Yarrowia lipolytica DSM 1345 Debaromyces hansenii DSM 3428 Hanseniaspora guilliermondii DSM 3432 Schwanniomyces occidentalis DSM 3451 Lipomyces starkeyi DSM 70295 11 Pichia. pastoris Zygosaccharomyces baili Saccharomycodes ludwigii Torulaspora delbrueckii Torulaspora pretoriensis Hanseniaspora uvarum Schizosaccharomy(.es poinbe Dekkera anomala Kluyveromyces marxianus i0 Pachysolen tannophilus Gandida boidini CandidA albicans DSM 70382 DSM 70492 DSM 3447 DSM 70504 DSM 70525 1MW 473 CBS 1043 CBS 4210 CBS 369 CBS 4045 CBS 5777 CBS 2730 In this collection of yeast topecies, four species are also represented which were previously -assigned to the genus Saccharomyces: C CC .g 4 *0 4 CC 44 C4 4 e44*4* 4

C*

Cl C CCI o 44CC

CC

C. 4 4

C

4 C 4.

Kluyveromyces marx.;anas Zyqosaccharomyces bailii Torulaspora delbrueckii Torulaspora pretoriensis ex Saccharomyces fragilis ex Saccharomyces lactis ex Saccharomyces elegans ex Saccharomyces fermentati ex Saccharomyces pretoriensis 'These four yeast species, which at the time were assigned to the genus Saccharomyces on the basis of morphological and physiological criteria, and which exhibit a high degree of similarity with the genus Saccharomyces as 25 regards taxonomic criteria, can thus be clearly delimited iimunodiagnostically from Saccharomyces cerevisiae using the monoclonal antibody 92-276/018.

None of these yeast species from different families reacted with the monoclonal antibody 92 276/018, either in the immunofluorescence test or in Western blot analyses.

Examp1i. 3 Further work examined the reactivity of the monoclonal 2% t: t" IQ; j-ft* 12 antibody 92 276/018 with different wild isolates of the species S. cerevisiae.

The following strains of S. cerevisiae were employed:

S.

S.

S.

S.

S.

S.

S.

S.

S.

S.

S.

15 S.

cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae cerevisiae DSM 70471 (ex.

DSM 70478 (ex.

DSM 70487 (ex.

DSM 70514 (ex.

CBS 5926 (ex, IMW 116 IMW 188 IMW IMW 92 VLSF 07158 J. Sainsbury, PLC YGSC X2180 1A ellipsoideus) chevallieri) diastaticus) italicus) boulardii) 4e .ll II 9 14 4.

9 14, 4 All these strains reacted with the monoclonal antibody, both in the Western blot and in the immunofluorescence test. The first four strains examined had previously been assigned to different Saccharomyces species which are now no longer universally accepted, and all of them have been added to the species S. cerevisiae.

Example 4 Further work examined the reactivity of the monoclonal antibody with different laboratory strains cf the species S. cerevisiae. The following table li ts the strains examined, their genetic markers and their reactivity with the monoclonal antibody.

-4 44 44 4$ PI 4 *4 4 2:5 :"i i

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i i: 13

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Table: Reactivity of the monoclonal antibody 92-276/018 with Saccharomyces cerevisiae laboratory strains Strain I Genetic Markers C13ABYSBG HT 393 79 S15O-2B TY 4 4STLU COY 1465 IA 258 ura3-2,leu2,his,pral,prbl,prcl,cps1 ura3 I eu2,pral prbl 1prcl cpsl lprel leu2,trpl leu2-3, leu2-112,ura3-52,trpI-289, his 3A1 ieu2 ,ura3, tsl leu2, ura3 ,tsl, erbi leu2 ,ura3, asci/pinr1 canl,ileu2, his4,met14, trpi,ura3,osel, SUC2 cani, ieu2,his4,znet14, trpI, ura3, OSE1, SUC2 4 4 1 4 0 All the strains reacted, independently of the genetic markers. S. cerevisiae strains having an altered cellwall structure or protein deletions in the periplasmic space due to genetic mutations, such as, for example, 4STLU, CGY 1465, TY 4 and A 258, were also recognized by the monoclonal antibody.

The laboratory strains of S. cerevisiae listed here are 20 predominantly used for recombinant DNA purposes, and serve, in particular, as host cells for expressing heterologous proteins. These strains are freely availablo, and are described in the literature with regard to their markers and possible uses. The specific references are: A 258 and A 259: *4 *4 4 *4 4 4* 4 44 CGY 1465: C13ABYS86 and HT 393: Sakai et al., Genetics 119, pp. 499-506 [1988].

Rudolph et al., Cell 58, pp.

133-145 [1989].

Heinemeyer et al., EMBO J.

pp. 535-562 [1991].

Waltschewa et al., Yeast pp. 313-320 [1989].

Baldari et al. EMBO J. 6, pp. 229-234 [1987].

Price et'- al., Gene 55, pp.

287-293 [1987].

±STLU and TY 4: S150-2B: r~1 79: -C 14 Example According to Barnett, ten species are nowadays assigned to the genus Saccharomyces. An investigation was next undertaken to determine whether the monoclonal antibody 92-276/018 reacts with the other nine species in addition to S. cerevisiae.

The monoclonal antibody 92-276/018 showed no reaction in a Western blot and in an immunofluorescence test with the following Saccharomyces species: S. exigus S. dairensis S. unisporus S. servazzii S. castelli S. kluyveri CBS 134 CBS 421 CBS 398 CBS 4311 CBS 4309 CBS 2861 1 i; 6

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r:i ;:i I: t a* 44 4i a 44 However, the monoclonal antibody recognized the species: S. bayanus S. bayanus S. bayanus S. pastorianus S. pastorianus S. paradoxus S. paradoxus S. paradoxus DSM 70412 DSM 70511 DSM 70547 DSM 6580 CBS 1260 CBS 406 CBS 2980 CBS 432 94 44 4 i S a4 4 44 It is evident, therefore, that antibodies against the gp 200 from S. cerevisiae, and, in particular, the monoclonal antibody 92-276/018, represent suitable agents for identifying the species S. cerevisiae or, alternatively, characterizing a yeast species other than S. cerevisiae to show that this species cannot possibly be S. cerevisiae.

-/l rather as varieties of S. cerevisiae.

Finally, it remains to observe that the systematics of the yeast genus Saccharomyces are of practical importance since some species are used in industry, in particular in the beer and wine industry, in the baking industry and in 15 The fact that the monoclonal antibody 92-276/018 recognizes the species S. paradoxus, S. pastorianus and S. bayanus in addition to S. cerevisiae is in no way to be regarded as indicating lack of specificity. Extensive DNA studies have revealed that S. paradoxus and S. bayanus exhibit an exceptionally high degree of relatedness with S. cerevisiae (Naumov et al., Yeast 8, 599-612 [1992]). In addition to this, the species S.

pastorianus is considered to be a hybrid of the species S. cerevisiae and S. bayanus. The high degree of similarity between the species mentioned here led Naumov et al.

to describe these Saccharomyces species as being sibling species of S. cerevisiae.

In connection with the fact that the underlying criteria, 15 and their weighting, for determining yeast species, are subject to variation and alteration with time, it could also be argued that the species S. paradoxus, S. pastorianus and S. bayanus are in no way to be regarded as independent species but rather as varieties of S. cerevisiae. However, even if Barnett's classification of the 0 species within the genus Saccharomyces is accepted as being valid, the monoclonal antibody is of great value; since it identifies a yeast isolate as belonging to the genus Saccharomyces and excludes several species within this genus.

Example 6 4* i If nitrocellulose paper, onto which proteins of S.

cerevisiae cell extracts have been transferred from polyacrylamide gels, is incubated in periodate solutions and the reactivity which remains is subsequently investigated using the monoclonal antibody 92-276/018, it is then observed that, following a 30-minute incubation in the presence of 0.1 mM periodate, the full reactivity is ^still present. By contrast, it was not possible to detect any binding of the monoclonal antibody 92-276/018 when the nitrocellulose strips were incubated in 10 mM or -16 mM periodate.

The reactivity is strongly affected when the incubation of the monoclonal antibody with the nitrocellulose coated with S. cerevisiae antigens is carried out in the presence of 100 mM methyl-a-D-methylmannoside. By contrast, the reactivity is undiminished as compared with the control, to which no sugars have been added, in the presence of methyl-a-D-methylglucanoside.

It can be concluded from these two findings that the i antigenic determinants which are recognized by the monoclonal antibody 92-276/018 probably represent carbohydrate structures, or represent peptide structures whose affinity for the antibody is influenced by carbohydrate sidechains.

15 In Western blot analyses, it is not only antigen which bands in SDS gels with an apparent molecular weight of 200 kDal which is recognized by the monoclonal antibody 92-276/018; rather, the specific reactivity extends over a relatively wide range from about 40 kDal to 200 kDal.

20 This indicates that mannoproteins or mannans are being recognized which are very heterogeneous in their molej. cular weight. It is probable that the monoclonal antibody recognizes a carbohydrate-specific epitope which can be a constituent of several glycoproteins or mannan structures and that gp200 represents only one antigen of several in S. cerevisiae having such an epitope.

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Claims (7)

1. A hybridoma DSM ACC2126 which secretes the monoclonal antibody DSM ACC2126.

2. A monoclonal antibody from DSM ACC2126.

3. An epitope or immunogenic moiety from Saccharomyces sensu stricto to which the monoclonal antibody DSM ACC2126 binds.

4. A monoclonal or polyclonal antibody which binds to epitopes or immunogenic moieties as claimed l laim 3 and which possesses the same antigenic speci.c y as the monoclonal antibody from DSM ACC2126. An epitope or immunogenic moiety as claimed in claim 3 which derives from Saccharomyces cerevisiae. 15 6. A diagnostic agent for identifying and quantify- ing Saccharomyces sensu stricto, which diagnostic agent contains antibodies as claimed in claim 2 or 4.

7. A diagnostic agent for detecting antibodies against Saccharomyces sensu stricto, which diagnostic agent contains epitopes or immunogenic moieties as claimed in claim 3.

8. A process for preparing monoclonal antibodies as claimed in claim 4, wherein S epitopes or immunogenic moieties from Saccharomyces sensu stricto which react with the monoclonal anti- body DSM ACC2126 are isolated; a suitable organism is immunized with the isolated immunogenic moieties; of the resulting monoojonal antibodies, those are selected which are specific for Saccharomyces sensu stricto.

9. A method for identifying or quantifying Sac- Scharomyces sensu stricto in a sample, wherein a) the sample is brought into contact with an anti- body as claimed in claim 2 or 4; b) the formation of antigen/antibody complexes is measured using suitable methods. A method for detecting antibodies against -18- Saccharomyces sensu stricto in a sample, wherein a) the sample is brought into contact with epitopes or immunogenic moieties as claimed in claim 3; b) the formation of antigen/ antibody complexes is measured using suitable methods. DATED this 23rd day of January 1995. VALq DU~flINGWEflKE A1CTIENESETLSIIArT VTT O, WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROJAD HAWTHORN. VIC. 3122. o O*ov Vtow, -I HOE 94/B 001 Ma 986 Dr.Bc/hg Abstract of the Disclosure Saccharomyces-specific antigens and antibodies, their preparation and use The invention relates to antigens which are specific for Saccharomyces cerevisiae, Saccharomyces bayanus, Sac- charomyces paradoxus and Saccharomyces pastorianus, and to antibodies directed against them. These antigens and antibodies can be employed for identifying and quantify- ing the said Sacchacomyces species. 9*6 C C e C C. v S* 4 4 3 i 0 a L